Address review findings on the lnw pointer read (#89)

- Share one lnw host regex between matches and the pointer validator so
  the two cannot drift apart.
- Resolve the pointer href against the page address before validating,
  so a relative pointer still yields its Series instead of silently
  resolving to type other.
- Pin pointer/breadcrumb agreement on the divergent page and pin that a
  pointer off-host or not /novel/<slug>/ resolves to other.

userscript/test/novel-logic.test.js

@@ -165,19 +165,63 @@ test("lightnovelworld.detect reads the Series identity from the page pointer on
 test("lightnovelworld.detect falls back to the breadcrumb when the pointer is absent", () => {
   reset();
   elements = { "h1.entry-title": "My Longevity Simulation Chapter 1" };
+  const url = "https://lightnovelworld.net/my-longevity-simulation-chapter-1/";
+  // Same divergent page, both pointers from the real markup (research note
+  // §3): breadcrumb position 2 must say what the All Chapter anchor says.
+  attrEls = {
+    "a[aria-label='All Chapter']": {
+      getAttribute: () => "https://lightnovelworld.net/novel/immortality-simulator/",
+    },
+  };
+  const viaPointer = lightnovelworld.detect(loc(url));
   attrEls = {
-    // Verbatim from the real page (research note §3): position 2 of the
-    // microdata BreadcrumbList is the Series.
     '[itemtype="http://schema.org/BreadcrumbList"] a[itemprop="item"][href*="/novel/"]': {
       getAttribute: () => "https://lightnovelworld.net/novel/immortality-simulator/",
     },
   };
-  const url = "https://lightnovelworld.net/my-longevity-simulation-chapter-1/";
-  const p = lightnovelworld.detect(loc(url));
+  const viaBreadcrumb = lightnovelworld.detect(loc(url));
+  assert.equal(viaBreadcrumb.type, "chapter");
+  assert.equal(viaBreadcrumb.seriesId, viaPointer.seriesId);
+  assert.equal(viaBreadcrumb.seriesUrl, viaPointer.seriesUrl);
+  assert.equal(viaBreadcrumb.seriesId, "immortality-simulator");
+  assert.equal(viaBreadcrumb.chapterSlug, "my-longevity-simulation");
+});
+
+test("lightnovelworld.detect resolves a relative pointer against the page address", () => {
+  // Defensive: every measured page ships an absolute pointer href, but a
+  // theme change could go relative — the pointer is still this page's own
+  // link back to its Series.
+  reset();
+  elements = { "h1.entry-title": "A Will Eternal Chapter 1298" };
+  attrEls = {
+    "a[aria-label='All Chapter']": { getAttribute: () => "/novel/a-will-eternal/" },
+  };
+  const p = lightnovelworld.detect(loc("https://lightnovelworld.net/a-will-eternal-chapter-1298/"));
   assert.equal(p.type, "chapter");
-  assert.equal(p.seriesId, "immortality-simulator");
-  assert.equal(p.seriesUrl, "https://lightnovelworld.net/novel/immortality-simulator/");
-  assert.equal(p.chapterSlug, "my-longevity-simulation");
+  assert.equal(p.seriesId, "a-will-eternal");
+  assert.equal(p.seriesUrl, "https://lightnovelworld.net/novel/a-will-eternal/");
+});
+
+test("lightnovelworld.detect rejects a pointer that is not a /novel/ address on its own host", () => {
+  // Counterfactual pointers, exercising the criterion that a pointer "present
+  // but not parseable as /novel/<slug>/ on lightnovelworld.net" must not
+  // become a seriesUrl the backend is later asked to Poll: off-host, and
+  // on-host but the wrong path shape.
+  reset();
+  elements = { "h1.entry-title": "My Longevity Simulation Chapter 1" };
+  const url = "https://lightnovelworld.net/my-longevity-simulation-chapter-1/";
+  attrEls = {
+    "a[aria-label='All Chapter']": {
+      getAttribute: () => "https://evil.example/novel/immortality-simulator/",
+    },
+  };
+  assert.equal(lightnovelworld.detect(loc(url)).type, "other");
+  attrEls = {
+    "a[aria-label='All Chapter']": {
+      getAttribute: () => "https://lightnovelworld.net/fiction/immortality-simulator/",
+    },
+  };
+  assert.equal(lightnovelworld.detect(loc(url)).type, "other");
 });
 
 test("lightnovelworld.detect resolves to other when the page carries no pointer", () => {